Mold Manufacturing
The requirements for mold design and production are: accurate size and smooth surface; Reasonable structure, high production efficiency, and easy automation; Easy to manufacture, long lifespan, and low cost; The design meets the process requirements and is economically reasonable.
The design and parameter selection of the mold structure must consider factors such as rigidity, guidance, unloading mechanism, positioning method, gap size, etc. The vulnerable parts on the mold should be easily replaceable. For plastic molds and die-casting molds, it is also necessary to consider a reasonable pouring system, the flow state of molten plastic or metal, and the position and direction of entering the mold cavity. In order to improve productivity and reduce runner pouring loss, multiple cavity molds can be used to complete multiple identical or different products simultaneously in one mold. High efficiency, precision, and longevity molds should be used in mass production.
The stamping die should use a multi-station progressive die, and a hard alloy insert progressive die can be used to improve its lifespan. In small batch production and new product trial production, simple molds with simple structure, fast manufacturing, and low cost should be used, such as composite dies, sheet metal dies, polyurethane rubber dies, low melting point alloy dies, zinc alloy dies, superplastic alloy dies, etc. The mold has begun to adopt computer-aided design (CAD), which involves optimizing the design of the mold through a computer-centered system. This is the development direction of mold design.
Mold manufacturing is divided into flat punching molds and cavity molds with space based on structural characteristics. The punching die utilizes the precise fit of the size between the convex and concave molds, and some even have a seamless fit. Other forging molds such as cold extrusion molds, die-casting molds, powder metallurgy molds, plastic molds, rubber molds, etc. are all cavity molds used to form three-dimensional shaped workpieces. The cavity mold has dimensional requirements in three directions: length, width, and height, and its shape is complex, making it difficult to manufacture. Mold production is generally single piece, small batch production, with strict and accurate manufacturing requirements, and often uses precision processing equipment and measuring devices.
The flat punching die can be initially formed by electric discharge machining, and then further improved in accuracy through methods such as forming grinding and coordinate grinding. Form grinding can be carried out using optical projection curve grinding machines, or surface grinding machines with reduced or repaired grinding wheel mechanisms, or using specialized form grinding tools on precision surface grinding machines. Coordinate grinding machines can be used for precise positioning of molds to ensure precise aperture and spacing. Computer numerical control (CNC) continuous trajectory coordinate grinding machines can also be used to grind convex and concave molds of any curve shape. The cavity mold is often processed using profiling milling machines, electric discharge machining, and electrochemical machining. The combination of profile milling and CNC machining, as well as the addition of a three way translational head device in electric discharge machining, can improve the machining quality of the cavity. Adding gas filled electrolysis in electrochemical machining can improve production efficiency.
